Some hollow fiber sintered metal, and ceramic crossflow membrane systems have included vertically oriented membrane components. However, many commercial membrane filtration plants, and especially those using spiral membranes, have installed the membranes in vessels that are oriented horizontally, or near horizontally.
While this allows for efficient processing during normal running, it is very inefficient during initial introduction of unprocessed product and removal of product on the retentate side of the membrane at the end of the production run. This can lead to excessive water use and is chemical intensive when the system is cleaned.
Prior to production the horizontally oriented membrane system is normally flooded with water or a suitable chemical solution because it is important to prevent the membranes from drying out. This has to be displaced by introduction of product into the retentate side of the membranes, leading to significant intermixing of the water or chemical solution and the product and resulting in dilution and possible chemical contamination of the product. The initial flow of diluted or contaminated product normally has to be diverted into the plant effluent stream and represents a financial loss to the production facility.
At the end of production the material on the retentate side of the membranes has to be displaced by water due to inefficient drainage from the horizontally oriented membranes. Diluted product at the end of production normally has to be diverted into the plant effluent stream and represents a financial loss to the production facility.
Extremely large volumes of water are needed to remove both product and chemicals, from the membrane system resulting in high potable water consumption and an excessive volume of wastewater. The problem is especially apparent when the retentate is of significantly high viscosity.